I’m sure there’s nothing wrong with you!
Keep track, and if it continues, you might consider getting on the pill. That should straighten it out, although it also has downsides. Might take a bit of tweaking to get the right estrogen/progestin dosing down.
Mine were always early, so I started on the pill at 19. Even after stopping the pill for a few months (after years of taking it) I found that they still were obnoxiously close together.
Whether you decide to go that route, or wait it out, you should probably see the OB/Gyn just to make sure everything is okay.